Lung cancer account for ~150,000 deaths annually in the United States alone and lung adenocarcinoma (LUAD), which is a subtype of non-small cell lung cancer accounts for half of all lung cancers. Current therapies for advanced-stage lung cancer do not provide durable clinical benefit and only 1% of the stage IV LUAD patients survive more than 5 years. Therefore, improved molecular understanding of LUAD initiation and progression is essential for developing effective therapies. Metabolic deregulation due to the alterations in metabolic pathways is one of the key hallmarks of cancer cells. However, the role of metabolic alterations in LUAD has neither been comprehensively analyzed nor fully understood. Therefore, to identify metabolic drivers of LUAD, we performed a large-scale in vivo RNAi screening and identified heparan sulfate 2-O- sulfotransferase 1 (HS2ST1) as a gene necessary for LUAD growth and metastasis. The central hypothesis is that metabolic alterations are crucial regulators of LUAD initiation, progression and therapy response. The overall objective is to determine the role of HS2ST1 in LUAD initiation and progression, ascertain its mechanisms-of-action and determine its clinical utility as a drug target for LUAD therapy. Specifically, in Aim 1, we will determine the role of HS2ST1 in lung adenocarcinoma initiation and progression. Specifically, we will determine if HS2ST1 is sufficient to transform immortalized lung epithelial cells and if it is necessary for oncogenic KRAS-induced transformation. Additionally, because HS2ST1 confers invasive phenotype to LUAD cells, we will investigate if HS2ST1 is necessary for LUAD progression. To do so, we will use cell culture-based models of immortalized human lung epithelial cells, established LUAD cell lines and orthotopic mouse models of LUAD tumor growth and progression. In Aim 2, we will determine the mechanism(s) of HS2ST1 action. First, based on our results that HS2ST1 inhibition leads to increased expression of PTEN tumor suppressor gene, we will test the role of PTEN in HS2ST1 mediated LUAD initiation and progression. Additionally, because HS2ST1 can potentially regulate WNT and TGF- pathways, the role of these pathways in mediating the driver function of HS2ST1 will also be determined. The experiments will include biochemical, genetic, cell culture and in vivo orthotopic mouse model of LUAD-based approaches. In Aim 3, we will evaluate HS2ST1 as a drug target for lung adenocarcinoma therapy. Towards this end, we will test the effect of HS2ST1 inhibitor surfen alone or in combination with US Food and Drug Administration (FDA) approved angiogenesis inhibitor bevacizumab for its ability to inhibit LUAD tumor growth in the orthotopic mouse model of LUAD tumorigenesis. Collectively, the results of our experiments will uncover novel driver genes and pathways in LUAD initiation and progression, significantly improve the molecular understanding of LUAD and reveal new drug targets and drug combinations for effective LUAD therapies.